Applications exist for multiple position switches to effect various types of operations. One such application is in conjunction with the keys of a computer or typewriter. In the relaxed position (when the key is not depressed) the first switch position, typically the "off" position, is attained. Depression of the key to a first distance or by means of a first force generally causes the operation of the typewriter or computer to form a particular symbol associated with that key. In many computer keyboards and typewriter keyboards, further depression of the key, usually with a greater force, causes the computer or typewriter to continuously repeat the symbol represented by the key. This constitutes the third state of operation of such a switch. Other applications exist, where a first position of the switch generally is the "off" position; the second position constitutes a first output, which may be utilized for any purpose, and a third position constitutes the third output, which, again, may be utilized for yet another purpose.
Frequently, three-position switches are provided with switch operators which have a neutral or central point. The operator is moved in one direction from the central point for the second position, and is moved in the opposite direction from the central point to effect the third position or operation from the switch. Such switches either use a slide mechanism or a rocking toggle lever to effect the desired operation. A disadvantage of such switches is that to move from the second position to the third position, or vice-versa, it is necessary always to go through the initial or rest position of the switch, which typically is the center location (whether a slide switch or a rocking toggle is utilized).
Many multiple position switches employ some type of spring bias to return the switch to its starting condition (typically, the off position) whenever the operating lever or plunger is released, that is when force no longer is applied to the operating lever or plunger. To accomplish this, it usually is necessary to employ one or more springs as part of the switch assembly. Thus, even a relatively simple switch operator involves a number of different parts, which require several assembly steps in the manufacture of the switch. This increases the complexity of the switch, increases its cost of manufacture, and also increases the chance for a failure of one or more of these parts in the continued life of the switch.
The patent to Wintriss U.S. Pat. No. 3,263,044 is directed to a three-position switch in which a floating bar made of metal is moved by plungers from a rest position to an operated position. One of the switch mechanisms disclosed in this patent uses three spaced magnets and a fulcrum to effect the positioning of the metal bar under the operation of two different plungers. The first plunger moves the bar from a rest position to a first operating position interconnecting a pair of the magnets. Additional downward pressure on the plunger has no further effect on the operation. To reset the switch, a second plunger is provided. That plunger then is depressed to snap the floating bar to another position, where the opposite end is attracted to one magnet and moved away from another magnet. Release of both of the plungers then allows the metal bar to return to its original position. Because magnets are located on both sides of the switch mechanism, two plungers are required. This switch does provide a sharp snap action operation, amounting to a three-position switch; but it relatively complex, and requires dual plungers or operating members in order to effect its operation.
It is desirable to provide a simplified three-position switch which overcomes the disadvantages of the prior art.